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RED BLUFF FWO: Biologists Learning More About Pacific and Western Lamprey
California-Nevada Offices , September 30, 2009
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A handful of juvenile Pacific lamprey collected by rotary screw trap by FWS RBFWO.
A handful of juvenile Pacific lamprey collected by rotary screw trap by FWS RBFWO. - Photo Credit: n/a
Fish biologist Jacob Cunha demonstrating use of the lamprey slot cleaner and video camera.  Photo by Laurie Stafford, FWS
Fish biologist Jacob Cunha demonstrating use of the lamprey slot cleaner and video camera. Photo by Laurie Stafford, FWS - Photo Credit: n/a
New Coleman National Fish Hatchery barrier weir fish ladder. Photo by RJ Bottaro, FWS
New Coleman National Fish Hatchery barrier weir fish ladder. Photo by RJ Bottaro, FWS - Photo Credit: n/a
Close-up of lamprey slot in Coleman National Fish Hatchery barrier weir fish ladder. Photo by Matt Brown, FWS
Close-up of lamprey slot in Coleman National Fish Hatchery barrier weir fish ladder. Photo by Matt Brown, FWS - Photo Credit: n/a
View of Coleman National Fish Hatchery barrier weir fish ladder with lamprey slot in the middle of the picture. Photo by Matt Brown, FWS
View of Coleman National Fish Hatchery barrier weir fish ladder with lamprey slot in the middle of the picture. Photo by Matt Brown, FWS - Photo Credit: n/a

By Matt Brown, Red Bluff Fish and Wildlife Office
As Fish and Wildlife Service biologists work to restore habitat and improve fish passage on Battle Creek in northern California, they are also learning more about lamprey, an ancient eel-like fish .

According to Kelly Whitton, a fish biologist at the Service’s Red Bluff Fish and Wildlife Office (FWO), little is known about lamprey, in part because they spend up to seven years buried in the sediment, where they are out of sight and out of mind.  Their under the stream-bed biomass has the potential to be huge, she said. 

“There is a real need for education and a greater public awareness of these incredible creatures,” said Whitton, “Education not just for the public, but professional fish biologists need to understand and identify the different species to lessen the impacts of  our fish restoration and passage projects on lamprey”

Some environmental organizations believe that lamprey on the west coast have drastically declined. In 2003, the Service received petitions to provide protections under the Endangered Species Act (ESA) to four lamprey species.  In 2004, the Service found the petition did not present enough substantial scientific or commercial information to warrant listing under the ESA, primarily because of the lack of information regarding the status and distribution of lamprey.  

“Exactly which species are present in different watersheds is largely unknown,” Whitton said.   “Most people don’t realize that many lamprey species are non-parasitic and not anadromous.  Indeed only a few of the western species are both anadromous and parasitic.”

The Red Bluff FWO has been gaining experience and learning more about lamprey during the course of salmon and steelhead restoration projects.  This information gained may prove useful to the Service’s in future lamprey nitiatives.

Lamprey Study

In 2007, as part of the Battle Creek Salmon and Steelhead Restoration Project, the Red Bluff FWO conducted a survey of the Battle Creek fish community.  One objective is to learn how the Restoration Project affects lamprey distribution and abundance in Battle Creek. The restoration project includes dam removals, new fish ladders, increased flows and changes in water temperature, all of which could have major affects on these fishes.  After the  Battle Creek Restoration Project is completed, the creek will be re-surveyed to detect changes in the distribution of fishes, including predators and competitors that may have been blocked by the dams.

The entrances, slots and orifices that salmon use to swim through fish ladders use fast flowing water to guide salmon upstream.  Many fish ladders were constructed with sharp, 90 degree corners.  Lamprey struggle to negotiate sharp corners, especially when they’re moving upstream against fast flowing water. 

Recent studies show that lamprey are better able to negotiate these structures if the corners are rounded, like boulders in a stream.  A new fish ladder at the Coleman National Fish Hatchery barrier weir has incorporated features to improve lamprey passage and monitoring. The entrance to the new ladder was built with rounded corners that allow lamprey to hold onto and move into the ladder.  A novel design, called a lamprey slot, was used to allow the fish to pass through the baffles in the Coleman NFH fish ladder.  The fish ladder has a series of baffles that create pools that salmon use to jump or swim upstream.  A large vertical slot through each baffle allows high velocity water and salmon in and out of each pool. 

The vertical slot can pose a problem for fish that have limited swimming or jumping abilities like lamprey.  Lamprey move upstream by holding onto flat surfaces like floors or walls and swimming for short bursts upstream until they latch onto the surface again.  Poor swimmers without the burst speed to make it through the fast water cannot latch on and are swept downstream.  The small lamprey slots hopefully provide a low velocity route through the baffle in a location that should be easy for lamprey to find and pass through. Lamprey slots were built into the lower corner of each baffle in the river ladder. Incorporating these lamprey slots into the ladder was easy- pieces of 2X6 were placed in the concrete forms resulting in 1.5" X 5.5" passages through the baffles (see picture).

The lamprey slots could become clogged with debris that would go undetected because the slots are at the floor of the fish ladder under at least 7 feet of turbulent water.  Staff from Red Bluff FWO built a tool combining a video camera and a cleaning hook on a long pole to allow for inspecting the slots and to clear out debris.  So far, the slots have not collected debris.

Fish ladder Monitoring

In the old ladder, the metal bar racks that guided fish past monitoring equipment worked well with salmon and steelhead.  However, the bar spacing was too wide, allowing lamprey to pass between the bars and elude detection in the counting station. The new ladder includes racks with 3/4 inch bar spacing that prevents Pacific lamprey from passing through the counting station undetected. This improved monitoring setup crowds salmonids and lamprey past a video camera used to record fish passage.  In our first two months of operation, we have already detected more adult lamprey passing than were seen in our previous 14 years of monitoring.  The increased lamprey count is not necessarily due to increased lamprey passage, but to our increased ability to count them. Earlier in the season, we use a fish trap to count salmon, and bar spacing on the trap still allows lamprey to elude detection.

Fish Rescue

In the course of implementing salmonid restoration projects, the Red Bluff FWO has been rescuing fish and learning a little more about lamprey.   When a stream channel is dewatered to allow in-stream construction, many aquatic organisms can be left high and dry.  Biological opinions for salmon and steelhead require the salvage of threatened and endangered fish, in part to monitor the impacts of the project.  While relatively few salmonids have been rescued, large numbers of juvenile lamprey have been salvaged, sometimes a thousand in a day.  This has helped us learn how to most effectively capture lamprey and identify the habitat characteristics of these secretive fish.

Filling knowledge gaps in western lamprey biology is essential to successful fish conservation, not only for lamprey, but for salmon and other fish species as well.  Among our new found knowledge is that small, low-cost improvements to dams and fish ladders can make a big difference to lamprey passage. Educating fish biologists and fish passage engineers about the possibilities could go a long way towards improving fish passage and protection of these once widespread fishes.

 

 

 

 

 


Contact Info: Matt Brown, 530-527-3043 x253, Matt_Brown@fws.gov



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